Process of making automobile bumpers and the like



Oct 16, 1934. G A LY 1,977,448

PROCESS OF MAKING AUTOMOBILE BUMPERS AND THE LIKE Original Filed Nov.E7, 1925 Patented Oct. 16, 1934 UNITED STATES PATENT OFFICE PROCESS orMAKING AUTOMOBILE BUMPERS AND THE LIKE George Albert Lyon, Allenhurst,N. J.

28 Claims.

This invention relates to a method of making automobile bumpers,bumperettes or bumper fittings.

In the manufacture of automobile bumpers,

6 certain of the surfaces are usually provided with a coating of nickel,japan, enamel or other coating material, in order to give a highlyattractive appearance to the finished bumper. In preparing the surfacesof the metal for the reception 10 of the coating of nickel or othercoating material, the surfaces are ground and polished. The shaping ofthe stock of which the bumper is formed usually requires the applicationof heat to reduce the metal to the proper condition for bending. Thetemperatures required in this op eration are such as to causeconsiderable oxidation of the surfaces of the metal. For this reason,the grinding and polishing of the surfaces of the stock have ordinarilybeen performed after the bumper has been heated and bent into its finalshape. This has been unsatisfactory on account of the inaccessibility ofcertain parts of the surfaces to be finished to the finishing tools.

The principal objects of the present invention are to improve theprocesses of manufacture of automobile bumpers and other articles of theclasses above stated and to produce an improved process of making theseproducts in which one or more surfaces of a strip of metal of which thebumper or the like is to be formed, are finished or polished while thestrip is in a simple form readily accessible to the finishing tools andin which the finished surfaces are protected more effectively fromoxidation during the heating, bending, hardening and temperingoperations than in processes heretofore devised.

With these and other objects in view, the invention consists in aprocess embodying the novel and improved features hereinafter describedand particularly pointed out in the claims, the advantages of which willbe readily understood by those skilled in the art.

In the present app'ication, the process is described with particularreference to the making of an automobile bumper, but it is to beunderstood that certain features of the invention may also be applied tothe making of other articles, such as bumper bars, bumperettes andbumper fittings. The process shown and described in this applicationcontains certain subject matter common to the present process, to thatdisclosed in applicants Patent No. 1,917,267 dated July 11, 1933, and tothat disclosed in applicants application Ser. No. 5,818, filed January30, 1925.

The invention will be clearly understood from the accompanying drawingillustrating certain steps in the process and the following detaileddescription of the various features of the process.

In the drawing: 1

Fig. 1 illustrates a piece of strip steel from which 6 the buffer is tobe formed;

Fig. 2 illustrates diagrammatically the manner in which the strip isbent into ring form;

Fig. 3 illustrates one method of surface grinding the strip after it isformed into a ring;

Fig. 4 illustrates the manner in which the rings or ring sections areheated preparatory to the forming operations;

Fig. 5 is a plan view of a mechanism which may be employed in theforming and quenching operations, this view showing the ring in placewith relation to this mechanism just before the initial formingoperation is performed;

Fig. 6 is a view in vertical section of the mechanism shown in Fig. 5,and illustrating certain of the parts in different positions; and

Fig. '7 is a view illustrating the step of temperlng the buffer after ithas been bent into its final shape.

In making a bumper by the novel process of the present invention, asteel strip such as shown in Fig. 1 of the desired cross-sectionaldimensions and of the length required to make a single bumper or anumber of bumpers of the desired design, is employed. This strip may beformed of untempered and unhardened stock of any desired steelcomposition, and is preferably from A" to in thickness and from 1 to 2in width. Highly satisfactory results have been obtained with steelstock containing from .30% to 33% of carbon, this steel being known inthe art as knife back steel. The finishing operations to prepare thesurfaces of the strip for a plating of nickel or other plating metal maybe performed when the strip is in a substantially straight or other barform. Certain of the finishing operations may also be performed afterthe strip has been bent into buffer form.

In finishing certain surfaces of the strip, while in a substantiallystraight or other, bar form, the strip may be subjected to the action ofrotary grinding wheels, graded to produce the proper finishes upon thefaces of the bumper. Ordinarily, both the back and front faces of thestrip are ground, although where it is desired to reduce the cost, oneface only of the strip, which is to form the outer face of tine finishedbumper may be ground. Both of the lateral faces of the strip, or bothedges of the strip may be ground or polished simultaneously by passingthe strip between rotary grinding or polishing wheels arranged inopposed relation.

Preferably instead of finishing the surfaces of the strip while thestrip is in substantially straight or other bar form, the strip isrolled while cold into the form of a ring, before the grinding andfinishing operations are performed. These operations may be performedmore quickly and efiiciently when the strip is in ring form. Theexpressions ring or ring form are to be understood as not necessarilyreferring to a perfect circular ring .but may include other ring shapeswhich are rotatable to present different portions of the ringsuccessively to the action of the finishing tools. The rolling operationmay be efficiently carried out in a three-roller bending machine asshown in Fig. 2, and the untempered and unhardened condition of thestock enables the same readily to be bent beyond the elastic limit ofthe steel permanently into a ring formation.

The strip having been rolled into ring form, the ends of the strip arewelded together, preferably by an electric welding operation, and theflash formed in the welding operation is then removed in any suitablemanner. The rolling operation will usually result in the formation of aslightly fiat portion at each end of the strip. After the ends of thestrip are welded together, the ring is preferably placed in an expandingor in a shrinking machine which reduces the ring to a substantiallyperfect circular form, the fiat portion at each side of the weld beingremoved in this operation. The forming of the strip into a ring whilecold loosens some of the mill scale and causes a considerable part ofthe same to flake 01!, thereby reducing the amount of labor and timethat would be required in removing the scale from the surface to befinished by grinding wheel in the first part of the finishing operation.

. The grinding and polishing of the ring preparatory to the plating maybe performed substantially in the manner described in my co-pendingapplications Serial No. 745,432, filed Octoberv 23, 1924, and No. 5,818,filed January 30, 1925. Both the inner. and outer faces of the strip maybe ground and polished simultaneously by rotating the ring in contactwith revolving grinding and polishing wheels. Thus both the inner andouter surfaces or the inner and outer edges of the bar or strip may befinished simultaneously by rotating the ring between opposed grinding orpolishing wheels as shown in Fig. 3. One face only of the ring may besubjected to the action of the finishing wheels, if only one face of thebumper is to be finished.

In finishing the surface of the straight bar on of the ring for thereception of the coating .of nickel or other plating, preferablyflexible wh'eels having different grades of emery surfaces are employedsuccessively, the wheels employed in successive operations increasing infineness. In the final finishing operation a wheel having a very fineemery surface is employed in connection with emery paste, which is agrease containing emery usually of the same fineness as the wheelitself. This wheel tends to smooth out or cause a surface flow of thesteel eliminating to a very large extent the grinding marks. Thisresults in the production of a very highly finished surface which isadvantageous in securing electrodeposition of nickel or other platingmetal.

The length of the strip which is initially employed in the presentprocess may be such as to form a number of bumpers, bumper bars,bumperettes or bumper fittings. The finishing of a strip of this length,either in bar form or in ring form may be performed much more quicklyand efficiently than the finishing of a number of relatively shortlengths or sections. The grinding and polishing operations are performedcontinuously from one end of the strip to the other and the materialrequires less handling than relative short lengths of material.

After the finishing operations have been performed on the strip, thestrip may be cut into a plurality of bars or ring sections of the lengthrequired for the bumper, bumper bar or other article to be produced.

The steel is preferably heated by immersing the same in a bath of fusedsalts having a temperature range between the melting point and theboiling point sufiiciently large to secure the desired degree of heatwhile the bath remains in a liquid condition. This bath material is ofsuch a character that it will have substantially no chemical action uponthe steel during its relatively short period of immersion in the bathand that it will adhere to the surface of the metal and protect the samefrom oxidation when the metal is removed from the bath. This salt bathmay consist of any salts or mixtures of salts found suitable to heat themetal to the required temperature during a relatively short periodwithout appreciable action on the metal and to protect the metal fromoxidation when removed from the heating bath. Preferably, however, thisbath consists of a mixture of 50% potassium chloride and 50% sodiumchloride, 9. bath of this kind having been found to produce the mosteflicient results in actual practice. Each 11 bar, ring, or ringsection, after the finishing operation, is immersed in the heating bathwhich is heated to a temperature between 1400 F. and 1550 F., dependingupon the carbon content of the steel. The bar, ring, or ring section isheated in this salt bath usually from two to three minutes. Theimmersion of the metal for this length of time in the salt bath issufficient to heat the metal to the proper temperature for bending intothe desired bumper form and for thereafter o hardening the metal anddoes not give the bath material sufficient time to attack the metal anddestroy or iniuriously alter the fine finish placed upon it in thepolishing operations.

The strips in ring, arcuate or other form may be heated in a salt bathina pot 2 setting in a crucible 4, as shown in Fig. 4.

When the steel has been immersed in the heating bath for the length oftime required to heat the metal to the proper temperature for bendingand hardening, it is removed from the heating bath with a coating ofbath material adhering thereto and bent into the desired shape. Thering, ring section or bar is preferably bent into the desired form byinserting the same in a suitable forming mechanism. When the metal isheated in ring form, the ring may be placed in a forming mechanism ofthe character disclosed in application, Serial No. 745,432, referred toabove and bent into shape by the action of this mechanism. Thismechanism is illustrated in Figs. 5 and 8 and comprises forming shoes 6and 8 secured together in pairs for engagement with the ring atdiametrically opposite points therein. These forming shoes are movableaway 5 from each other to elongate the ring, and the shoes of each pairare hinged together so that they may be moved into substantiallyparallel planes, as shown in Fig. 6, to form an end fold buffer.

While the metal is still at a high temperature. and preferably whilestill held by the forming mechanism, it is immersed in a suitablequenching bath. The forming shoes 6 and 8 may be arranged over a tank 10containing the quenching bath 12. After the forming shoes have beenmoved relatively to elongate the ring and to bend the same into thedesired buffer form, the shoes are moved downwardly to carry the bufferinto the quenching bath, as shown in Fig. 6. After the quenching of themetal the shoes are first moved relatively toward each other and arethen moved upwardly to carry the buffer out of the tank. A quenchingbath is selected which will quickly dissolve the coating of the mixtureof sodium and potassium chlorides from the heating bath adhering to thesurface of the metal and which will harden the metal uniformly to thedesired degree. The quenching bath employed should also be such as toprevent the formation of oxide on the metal surfaces while cooling andalso to provide an adherent coating for protecting the surface of themetal from rapid oxidation when it is removed from the bath.

Quenching baths suitable to produce these results may be made up ofvarioussubstances or mixtures. In actual practice, a bath of thefollowing proportions has been found to produce highly efficient andsatisfactory results:

500 gallons of water 250 pounds of sodium chloride- 125 pounds of sodiumcyanide 50 pounds of lime When the steel is plunged into this quenchingbath, the salt coating of the heating bath is instantly removed from themetal and the metal is cooled rapidly and uniformly. The'solldconstituents of this bath left upon the steel by the evaporation of thewater when the steel is removed from the bath protects the metal fromrapid oxidation.

When a days time is to elapse between the removal of the bumper from thequenching bath and the placing of the bumper in the plating bath,thequenching bath is thoroughly agitated to keep the ingredients of thebath in suspension. This causes a relatively heavy coating of the bathconstituents to be formed upon the metal when it is removed from thebath to protect the surface from rapid oxidation.

When the steel is to be plated within an hour or two after it is removedfrom the quenching bath, the quenching bath is not agitated but theprecipitates are allowed to settle to the bottom of the bath.

The coating of the quenching. bath materials may be easily removed fromthe steel by washing the same in water.

After the formed bumper has been immersed in the hardening bath, it isremoved from the bath preferably while it still retains some of itsoriginal heat and is then allowed to cool slowly to room temperature. Aslight draw is thus imparted to the steel. The hot metal causes therapid evaporation of the water from the fllm of quenching bath solutionadhering to the bumper when it is removed from the bath, leaving acoating of the solid constituents of the bath thereon. During thequenching operation, sizzling takes place while the metal is cooling,which gradually diminishes and this constitutes an indication as to theproper time for withdrawing the steel from the bath.

During the quenching operation the bumper is subjected to heavy internalstresses and should then be held from distortion by suitable mechanism.The bumper may be held on the forming mechanism during the quenchingoperation to hold the same from distortion.

Instead of removing the bumper from the quenching bath while it retainssome of its original heat, it may be left in this bath until it hascooled substantially to the temperature of the bath and then removedfrom the bath and heated to a suitable temperature to draw the temper tothe desired degree. The heating of the bumper to temper same may beperformed by placingthe bumper in a suitable heating bath as describedin applicants co-pending application, Serial No. 5,818, filed January30, 1925. Fig. lshows the formed buffer immersed in a heating bath 14contained in a pot 16. This pot is inserted in the crucible '18. Thetemperature suitable for this operation, I have found to be between 600F. and 800 F., depending upon the carbon content of the steel.

The immersion of the-metal in the heating and quenching baths removesall traces of the grease which may remain on the metal after the finalfinishing of the same with emery paste. This is highly important since afilm of grease upon the surface of the steel to which the platingmaterial is to be applied may ruin the plating operation. The bumper,after removal from the quenching bath and after its temper is drawn issubjected to a cleansing operation before receiving further treatmentfor the production of a finished bumper. When the bumper is to benickled it is placed in a bath of hot alkali in order to remove any oilon the surface which may come from the hands of the operator or from thecontact of the bending mechanisms therewith. To increase theeffectiveness of the grease-removing action an electric current ispreferably passed through the solution with the bumper as one pole andwith the tank as the opposite pole, thereby setting up an electrolyticaction in the solution. The alkali solution not only removes any oil orgrease but also assists in the removal of the sodium cyanide and sodiumchloride and other substances of the sodium bath adhering to the bumper.The bumper is then thoroughly'washed in water to remove the alkali andis then placed in a pickling solution of hydrochloric or other suitableacid. to remove any traces of oxide which may have formed at the pointsat which the forming mechanism contacted with the bumper during theforming operation, thus excluding the quenching medium from contact atthese points. This oxide is ordinarily removed by allowing the bumper toremain in the pickling solution from 15 to '30 seconds. The bumper isthen removed from the pickling solution, and is thoroughly washed inwater to remove all traces of the acid.

The bumper, after it is cleansed in the manner above described, is readyfor insertion in the plating bath. The plating operation may beperformed in accordance with any of the usual methods to secure adeposition of plating metal of the desired thickness upon the finishedsurface of the bumper. After the plating operation the bumper is againwashed to remove all traces of the plating solution and is then dried.Theplated surfaces of the bumper are then preferably subjected to theaction of rotating bufiing wheels to give these surfaces a high polish.

When a relatively thin strip of steel stock having a highly polishedsurface is heated to harden- All cept that the reflecting surfaces orfacets are not nearly so pronounced. As the treatment of the-steel isvaried to impart diminishing degrees of hardness to the same, thesefacets become smaller and smaller until, with a treatment which impartsa relatively low degree of hardness to the steel, they-practicallydisappear. These individual reflecting surfaces reflect the light inmany different directions as compared with the smooth or plane surfacesformed under ordinary conditions and thus give a very distinctiveappearance to the nickel surface of the bumper.

If it is desired to manufacture a bumper having an unground surface inaccordance with the present process, the grinding and polishingoperations may be eliminated. The strip of steel in the form of a ringor in any other simple form without any preliminary surface finishing orgrinding, but with the mill scale adhering thereto, can be inserted inthe salt heating bath, formed into bumper or other shape and thenquenched in the quenching solution. The heating of the metal and theimmersion of the same in the quenching solution removes practically allthe mill scale so :that the bumper, after washing and drying, is readyto receive .a coating of japan, enamel or similar coating material.However, if it is desirable topolish one surface of the strip of steel,this surface can be ground, leaving the mill scale on the edges of thestrip and on the opposite surface thereof. When the strip is theninserted in the salt heating bath and thereafter'is immersed in thequenching solution, the mill scale is substantially removed and thebumper can then be nickel-plated or japanned. When this method isfollowed, the bumper after receiving a coating of japan or nickel willbe provided with a smooth surface having a high polish on the outsideonly of the bumper. When the bumper is to be nickel-plated, it isimportant to remove the mill scale completely on the surfaces to beplated. The immersion of the metal in the heating and quenching bathsdoes not produce this result but there are very minute surfaces wherethe scalestill adheres. This is not objectionable when the bumper isjapanned or enameled. When the bumper is nickeled, these minuteparticles of scale are removed in the pickling operation.

In making an unplated bumper in accordance with the present process, thebumper after removal from the quenching bath and after its temper isdrawn, is thoroughly washed in water and dried. A coating of japan,enamel or other suitable coating material may then be applied to thesurface of the bumper to give the same the desired finish.

Having explained the nature and object of the invention, and havingspecifically described the manner in which the invention may be applied,what I claim as new is:

l. The process of making automobile bumpers and the like. whichcomprises the finishing of a strip of unhardened steel for the receptionof a nickel or other coating, heating said strip in a fused salt bath tohardening temperature, bending the heated strip into bumper or otherform while a coating of the fused salt remains thereon, plunging thesame into an aqueous quenching medium which hardens the metal andproduces a mottled effect on the finished surface and at the same timeremoves the adherent coating of the salt therefrom, withdrawing theformed bumper or the like from the aqueous quenching medium while stillat a temperature sufiicient for drawing the temper of the steel andcausing the rapid evaporation of the water portion of the quenchingmedium, leaving its solid constituents on the surface of the steel toprotect the surface from rapid oxidation, and thereafter cleaning andapplying a finishing coating.

2. The process of making automobile bumpers and the like, comprising therolling of a strip of unhardened steel into ring form, finishing thestrip while in ring form for the reception of a nickel or other coating,heating said ring in a fused salt bath to hardening temperature, bendingthe ring into bumper or other form while a coating of the fused saltremains thereon, plunging the ring into an aqueous quenching mediumwhich hardens the metal andproduces a mottled effect on the finishedsurface and at the same time removes the adherent coating of the salttherefrom, withdrawing the formed bumper or the like from the aqueousquenching medium while still in a heated state, thereby drawing thetemper of the steel and causing the rapid evaporation of the waterportion of the quenching medium, leaving its solid constituents on thesurface of the steel to protect the surface from rapid oxidation,thereafter cleaning and applying a finishing coating.

3. The process of making automobile bumpers and the like, comprising thefinishing of a strip of unhardened steel for the reception of a nickelor other coating, heating said strip in a fused salt bath to hardeningtemperature, bending the heated strip into bumper or other form while acoating of the fused salt remains thereon, plunging the same into anaqueous quenching medium which hardens the metal and removes theadherent coating of the salt therefrom, removing the formed bumper orthe like from the aqueous quenching medium while still at a temperaturesufliciently high for tempering the steel and causing the rapidevaporation of the water portion of the quenching medium, leaving itssolid constituents on the surface of the steel to protect the surfacefrom rapid oxidation, thereafter cleaning and applying a finishingcoating.

4. The process of making automobile bumpers and the like, comprising therolling of a strip of unhardened steel into ring form, finishing thestrip while in ring form for the reception of a nickel or other coating,heating said ring in a fused salt bath to hardening temperature, bendingthe heated ring into bumper or other form while a coating of the fusedsalt remains thereon, plunging the ring into an aqueous quenching mediumwhich hardens the metal and removes the adherent coating of the salttherefrom, withdrawing the formed bumper or the like from the aqueousquenching medium while still at a temperature sufficiently high fordrawing the temper of the steel and causing the rapid evaporation of thewater portion of the quenching medium, leaving its solid constituents onthe surface of the steel to protect the surface from rapid oxidation,

thereafter cleaning and applying a finishing coating.

5. The process of making automobile bumpers and the like,-comprising theheating of a strip of unhardened steel in a fused salt bath to hardeningtemperature, bending the heated strip into bumper or other form while acoating of the fused salt remains thereon, plunging the same into anaqueous quenching medium which hardens the metal and removes theadherent coating of the salt therefrom and also removes substantiallyall of the mill scale, withdrawing the formed bumper or the like fromthe aqueous quenching medium while still at a temperature sufficientlyhigh to draw the temper of the steel and to cause the rapid evaporationof the water portion of the quenching medium, leaving its solidconstituents on the surface of the steel to protect the surface fromrapid oxidation, thereafter cleaning and applying a finishing coating.

6. The process of making automobile bumpers and the like, comprising therolling of a strip of unhardened steel into ring form, heating saidringin a fused salt bath to hardening temperature, bending the heated ringinto bumper or other form while a coating of the fused salt remainsthereon, plunging the ring into an aqueous quenching medium whichhardens the metal and removes the adherent coating of the salt therefromand also dislodges substantially all of the mill scale, withdrawing theformed bumper or the like from the aqueous quenching medium while stillat a temperature sufliciently high to temper the steel and to cause therapid evaporation of the water portion of the quenching medium, leavingits solid constituents on the surface of the steel to protect thesurface from rapid oxidation, thereafter cleaning and applying afinishing coating.

7. The process of making automobile bumpers and the like, comprising therolling of a strip of unhardened steel into ring form, finishing theouter surface of the ring for the reception of a nickel or othercoating, heating said ring in a fused salt bath to hardeningtemperature, bending the heated ring into bumper or other form while thecoating of the fused salt remains thereon, plunging the same into anaqueous quenching medium which hardens the metal and removes theadherent coating of the salt therefrom and also removes the greater partof the mill scale from the unfinished surfaces, withdrawing the formedbumper or the like from the aqueous quenching medium while still at atemperature sufficiently high for drawing the temper of the steel andcausing the rapid evaporation of the water portion of the quenchingmedium, leaving its solid constituents on the surface of the steel toprotect the surface from rapid oxidation, thereafter cleaning andapplying a finishing coating.

8. The process of making automobile bumpers and the like, whichcomprises the finishing of a strip of unhardened steel for the receptionof a nickel or other coating, severing said strip into a plurality ofsections, heating said strip sections in a fused salt bath to hardeningtemperature, bending the said sections into bumper or other form while acoating of the fused salt remains thereon, plunging said sections intoan aqueous quenching 'medium which hardens the metal and produces amottled effect on the finished surfaces and at the same time removes theadherent coating of the salt therefrom, withdrawing the formed bumpersor the like from the aqueous quenching water portion of the quenchingmedium, leaving 1 the solid constituents on the surface of the steel toprotect the surface from rapid oxidation and thereafter cleaning andapplying a finishing coatmg.

9. The process of making automobile bumpers and the like, whichcomprises the finishing of a strip of unhardened steel for the receptionof a nickel or other coating, severing said strip into a plurality ofsections, heating said strip sections in a fused salt bath to hardeningtemperature, bending the heated strip sections into bumper or other formwhile the coating of the fused salt remains thereon, plunging saidsections into ,an aqueous quenching medium which hardens the metal andremoves the adherent coating of the salt therefrom, removing the formedbumpers or the like from the aqueous quenching medium while still hot,thereby tempering the steel and causing the rapid evaporation of thewater portion of the quenching medium, leaving its solid constituents onthe surface of the steel to protect the surface from rapid oxidation,thereafter cleaning and applying a finishing coating.

10. The process of making automobile bumpers and the like, comprisingthe finishing of one lateral surface of a strip of unhardened steel forthe reception of a nickel or other coating, severing said strip intosections, heating said strip sections in a fused salt bath to hardeningtemperature, bending the heated strip sections into bumper or other formwhile a coating of the fused salt remains thereon, plunging the stripsections into an aqueous quenching medium which hardens the metal andremoves the adherent coating of the salt therefrom and also removes agreaterpart of the mill scale from the unfinished surfaces, andwithdrawing the formed bumpers or the like from the aqueous quenchingmedium while still hot, thereby tempering the steel and causing therapid evaporation of the water portion of the quenching medium, leavingits solid constituents on the surface of the steel to protect thesurface from rapid oxidation, thereafter cleaning and applying afinishing coating. t

11. The process of making automobile bumpers and the like, comprisingthe' finishing of a strip of unhardened steel for the reception of "anickel or other coating, severing said strip into a plurality ofsections, heating said strip sections in a fused salt bath to hardeningtemperature, bending the heated strip sections into bumper or other formwhile a coating of the fused salt remains thereon, plunging the sameinto an aqueous quenching medium which hardens the metal and removes theadherent coating of the salt therefrom, withdrawing the formed bumpersor the like from the aqueous quenching medium and tempering the steel,thereafter cleaning and applying a finishing coating.

12. The process of making automobile bumpers and the like whichcomprises the finishing of a strip of unhardened steel for the receptionof a nickel or other coating, severing said strip into a plurality ofsections, heating said strip sections in a fused salt bath to hardeningtemperature, bending the heated sections into bumper or other form whilea coating of the fused salt remains thereon, plunging the same into anaqueous quenching medium which hardens the metal and removes theadherent coating of the salt therefrom, withdrawing the formed bumpersor the like from the aqueous quenching medium and tempering the steel,thereafter cleaning and applying a finishing coating.

13. The process of making automobile bumpers and the like whichcomprises the rolling of a strip of unhardened steel into ring form,finishing the strip while in ring form for the reception of a nickel orother coating, severing said ring into a plurality of ring sections,heating said ring sections in a fused salt bath to hardeningtemperature, bending the heated ring sections into bumper or other formwhile a coating of the fused salt remains thereon, plunging the ringsections into an aqueous quenching medium which hardens the metal andremoves the adherent coating of the salt therefrom, withdrawing theformed bumpers or the like from the aqueous quenching medium andtempering the steel, thereafter cleaning and applying a finishing coati14. The process of making automobile bumpers and the like, comprisingthe heating of a strip of unhardened steel in a fused salt bath tohardening temperature, bending the heated strip into bumper or otherform while a coating of the fused salt remains thereon, plunging thesame into an aqueous quenching medium which hardens the metal,withdrawing the formed bumper or the like from the quenching mediumwhile still sufficiently heated to cause the relatively rapidevaporation of the water portion of said medium, leaving its solidconstituents on the surface of the steel to protect the surface fromrapid oxidation, thereafter cleansing the steel and applying a finishingcoating.

15. The process of making automobile bumpers and the like, comprisingthe rolling of a strip of unhardened steelinto ring form, heating saidring in a fused salt bath to hardening temperature, bending the heatedring into bumper or other form while a coating of the fused salt remainsthereon, plunging the ring into an aqueous quenching medium whichhardens the metal, withdrawing the formed bumper or the like from thequenching medium while still sufliciently heated to cause the relativelyrapid evaporation of the water portion of said medium, leaving its solidconstituents on the surface of the steel to protect the surface fromrapid oxidation, thereafter cleaning and applying a finishing coating.

16. The process of making automobile bumpers or the like which comprisesheating a strip of unhardened steel in a fused salt bath to hardeningtemperature, bending the heated strip into bumper or other form while acoating of the fused salt remains thereon, plunging the same into anaqueous quenching medium which hardens the metal, withdrawing the formedbumper or the like from said medium while still heated, and thereaftercleaning and applying a finishing coating.

1'7. The process of making automobile bumpers or the like, comprisingthe rolling of a strip. of unhardened steel into ring form, heating saidring in a fused salt bath to hardening temperature, bending the heatedring into bumper or other form while a coating of the fused salt remainsthereon, plunging the same into an aqueous quenching medium whichhardens the metal, withdrawing the formed bumper or the like from saidmedium while still he ted, and thereafter cleaning and applying a furaing coating.

18. The process of making automobile bumpers or the like, comprisingfinishing a surface of a strip of steel for the reception of a nickelcoating, bending the strip into the desired bumper or other form, andplating with nickel the finished surface of the strip.

19. The process of making automobile bumpers which comprises heating arelatively narrow strip of steel to a temperature suitable for bendingthe same, bending the strip into the required bumper or other shape, andquenching the steel in an aqueous quenching bath containing mineralsalts for protecting the surface of the steel from oxidation whenremoved from the bath.

20. The process of making automobile bumpers and the like whichcomprises heating a strip of steel in a fused salt bath to bendingtemperature, bending the heated strip into bumper or other form while acoating of the fused salt remains thereon, plunging the steel into anaqueous quenching medium containing mineral salts to protect the surfaceof the steel, and withdrawing the formed bumper or the like from thequench-- ing medium while still sufliciently heated to cause the rapidevaporation of the water portion of said medium, leaving its solidconstituents on the surface of the steel to protect the same from rapidoxidation.

21. The process of making automobile bumpers and the like comprising theheating of a strip of steel in a fused salt bath to bending temperature,bending the heated strip into bumper or other form while a coating ofthe fused salts remains thereon, plunging the bumper into an aqueousquenching medium and withdrawing the formed bumper or the like from themedium while still heated.

22. The process of making automobile bumpers or the like which comprisesheating a strip of steel to a relatively high temperature and plungingthe strip into a quenching bath having a relatively low temperature andcontaining suitable salts to protect the surfaces of the steel.

23. The process of making automobile bumpers and the like whichcomprises heating a strip of steel in a bath of fused salts to arelatively high temperature and plunging the strip into a quenching bathcontaining suitable salts to protect the surfaces of the steel.

24. In a process of making automobile bumpers, heating a strip of steelto a relatively high temperature, plunging the strip into a quenchingbath, removing the strip from the bath while hot, and allowing the sameto cool.

25. In a process of making automobile bumpers, heating a strip of steelto a high temperature, bending the strip into the required bumper orother shape, plunging the strip into a quenching bath, removing thestrip from the bath whiie still hot and allowing the same to cool.

26. In a process of making automobile bump-

